The present disclosure relates to a device and a method for generating an intermitted signal at least part of which is an oscillation signal with a characterising frequency and a constant phase at start-up, suited for communication systems, in particular for Ultra-Wide Bandwidth (UWB) applications.
Devices designed to generate signals with a controlled frequency are commonly used in a variety of applications. Typical examples are radio transmitters, transmitters and receivers in telecommunications, computer devices and other electronic applications where it is desired to stabilize a generated signal or to detect signals in the presence of noise.
Traditionally, the controlled frequency is implemented by a phase locked loop (PLL). This is a closed-loop feedback control system that generates and outputs a signal in relation to the frequency and phase of a reference signal. The PLL comprises of a phase detector, a variable oscillator, and a feedback loop. The circuit reacts to both the frequency and the phase, automatically raising or lowering the frequency of the variable oscillator until there is a match with both the frequency and the phase of the reference signal.
A disadvantage of this technique is the large start-up time for both phase and frequency compensation, demanding significant power. This is not well suited for many battery-operated, portable and hand held device applications. A second drawback of this approach is the accumulative jitter process typically initiated by the voltage controlled oscillator (VCO) (in series with jittery circuitry).
Another idea is presented in European Publication EP-A 0601780. A technique is described for a programmable frequency generator. The frequency is established in a ring oscillator. This is done by a set of transistors that supply an operating current to the ring. The device can be turned off to reduce the power supply. The tuning in phase and frequency is solely done by adapting the frequency. This approach results in a reduced accuracy and slows down the process.
It is an aim of the present disclosure to provide a device and a method for generating an intermitted signal with a characterising frequency in a very fast, accurate way consuming little power.
This aim is believed to be achieved with the use of devices and methods as described herein.